Filtering or dewatering press



A TEN 308G511 FSLTERING'OR'DEWATEHWG PRESS.

I APPL'ICATIQN'HLED APR. 24, I920. 1,366,307.

Patented Jan. 18, 1921.

WITEHJ? 17 i I Iwvev I A. tenjo sc UNITED STATES PATENT, OFFICE.

ABRAHAM TEN BOSCH, or THE HAGUE, NETHERLANDS, AssfGNO To NAAMLOOZE VEnNoo'rsoHAP NEDERLANDSGHE VEENVERWERKING MAATSCHAPPIJ', on THE HAGUE, NETHERLANDS, A COMPANY OF HOLLAND.

FILTERING OR DEWATERING PRESS.

Application filed Apri1 24, 1920. Serial No. 376,369.

To all whom it may concern: I

Be it known that I, ABRAHAM TEN Boson,

a subject of the Queen of the Netherlands,"

residing at The Hague, Netherlands, have invented certain new and useful Improvements in Filtering or Dewatering Presses, of which the following is a Specification.

This invention relates to filtering ordewatering presses.

If it is desired to dewater by means of a filter press peat, the colloidalstate'of which has been destroyed by a pie-treatment under pressure at an increased temperature, many quence the pressure in the cylinderfapidly increases. Underthese conditions a pulpy mass accumulates behind the filtering material, which mass including the fibrous material contained therein is' forced right through the strainer when the pressure 1n the cylinder rises to a certain limit; a considerable part of the fibers may thus escape through the filtering material; It has now been found that an excellent expression of the pretreated peat may be obtained in a press whose piston'or cylinder cover orrboth is or are of such formation that the outlet is formed by one or a plurality of narrow, for instance annular slots which are in communication with the cylinder through a space, the cross sectional area of which gradually decreases in a direction from the interior of the cylinder to the said slot or slots. of the invention the piston has the formof a hemisphere. The cylinder cover may have the same shape and, if desired, be movable in a sense opposite that of the piston.

Another feature of my invention is the provision of ajacket. inclosing the cylinder and allowing the material to be heated. It has been proved by experiment that the press may also be used for expressing water from peat which has not been pretreated under pressure at increased temperature.

Still another feature of my present invention 'is the provision of narrow slots in the piston or the cylinder cover or both, said slots during the pressing operation being in communication at one SlClGWltll the afore- In a convenientembodiment 7 said space of gradually decreasingcross-sectional area, and at the other side with the atmosphere. Thlsconstructionallows of an excellent dewatering of the central portion of the mass in the cylinder.

According to still another feature of the invention the cylinder space is in communication with the heating jacket through narrow slots the width of which preferabl increases in the direction of the jacket. hese additional slots in the 'walls of the cylinder insure a very rapid expression of moisture. and their increasing width in the direction of the jacket reduces the resistance against the outflow of water and, consequently, the chance of their getting choked up. A very convenient construction is realized ,b composing the cylinder of a plurality of annular sections placed the one on the other and let slots of said cylinder all that is required .is replacing the said distance pieces by others of different thickness.

Other features of the invention will be more particularly pointed out in the claims. The annexed drawing illustrates by way of example a longitudinal sectional view of a press constructed in accordance with my present invention.

' Theiillustratedpress comprises a cylinder 1, a longitudinally slotted reciprocable piston 2 provided with a hemispherical head and a central passage 3, and a hemispherical cylinder cover 4. Between the cylinder wall and the curved surface of the head of piston 2 is the above space of gradually ,de creasing cross-sectional area, ending in a narrow annular slot 5.

Thehead of piston2 is composed of a plurality of biconcave disks 6; its cap, how-.

mately triangular cross-sectional shape, and

their inner'edges are kept spaced equally apart by distance pieces 12.

The cylinder cover 4 isnot provided with openings, but between the base of'said body and the inner wall of the cylinder 1 is a.

narrow outlet slot 13;

The cylinder 1 is inclosed by a jacket 14 having a steam inlet nozzle 15 and a water dischargenozzle 16. p I

The method of operation of the press is as follows:

After the cylinder 1 has been filled with rawpeat, through the end'in which the cyl-' inder a is arranged, thepiston 2 is forced Y inward until the pressure in the cylinder is about lbs. Qwing to this pressure the rawpeat, which originally contained some 90% of water, releases part of itsmoisture which escapes mainly through the annular slot 5, but also through slots formed between the biconcave disks 6, and through the slots between the lower cylinder sections 9. I Said moisture is allowed to 'flow oiffin some convenient"manner. vAfter this preliminary pressing operation the material adjacent to the piston 2 contains considerably less moisturethan that in the remainder off cylinder 1. I K

Subsequently, the outlet 16 i closed, and superheated-steam ofsay 150 C. is admitted into the jacket 14, through nozzle '15. said steam penetrates into the cylinder through the slots between the annular sec.

tions 9, and heats the peat seas to destroy its colloid-a1 state. During or after this steaming the piston 2 is forced arther into the cylinder to reduce the percentage of moisture in the peat to 30:35.75, and the water now. expressed escapes mainly through.

the slot 13 and throughthe slots between the upper sections 9. I

In a press as described the dewatering action in the piston head may be so intense,

1 that thebriquet in the press strongly ad- 'heres to this head and cannot be removed without'being damaged. In order to overcome. this difliculty it is very convenient to couple/the piston 2 with means such as a ring 17 with handles for imparting to it a rotary motion about its axis during or at the end of the pressing operation, whereby the briquet is released, for" the briquet itself cannot follow this rotary motion seeing that the frictional resistance of the cylinder walls, as a rule, eXce eds that of the curved .surface of the head.

In the press illustrated the curved surfaces of thedisks 6 form together a spherical 6.0. "a particular disk being slightly greater than surface owing to the area of the top face of that of the bottom face of the next higher disk. I That is to say, said disks have along theircircumference and at right anglesto the direction of motion of the piston an annular The r surface which is in direct contact'with the material to be treated, and in many instances the presence of said annular surfaces favorably affects the expression of the peat. 1f the area of the top face of any particular disk were equal to that of the bottom face of the next higher disk, then owing to the a pr sence of the distance pieces 7 the curved surfaces of the disks would not form a spherical; surface, and the above annular surfaces would not be present. struction may be of value for the expression of water from certain other materials.

The briquet produced in the cylinder, may

' be removed from the press with a temperature of say 100 C. after which it may be crushed and, for instance,fed into a gas producer. However, the said briquet may also be pulverized and dried until its percentage of moisture is about l5%, after which the pulverized material may again'be passed into briquets having a calorific value of about 5000 cal. V a I It is'obvious that the filling ofthe cyliir der, the pressing operation, the admission of steam, etc., may be carried out automatically, but the manner in which this maybe doneidoes not form part of the present invention. 7

As already stated, thecylinder cover 4 might be made to act. as api'ston, when the This con piston 2 could. be stationary, or the said members might be made .to move simultaneously in opposite directions. 7 V

is to the'cylinder cover and the plston head, these need not; necessarily be formed as hen-iispheres, as they may have the form of a cone, or of an ellipsold, or any other convenient form, provided the space in closed between their surface and the cylinder wall has a gradually decreasing cross-.

sectional area. Furthermore, thesaidpiston head or cylinder cover or both. maybe so formed that the narrow outlet slots corresponding to slots 5 and 13 are not circular but, for instance, run in a diametrical direction. lnthis case the space of gradually decreasing crosssectional area may be formed between two cylindrical surfaces.

It will further be understood. that the heating of the peat mayv be effected by vmeans of hotair, or any other hot fluid, in-

eluding a cylinder, a piston in the cylinder consisting of a body longitudinally slotted on its outer surface for communication with the cylinder, and a head on the body shaped so as to leave an annular space between the head and the cylinder and the cross sectional area of the space decreasing in the direction from the end of the head to the slotted surface of the body of the piston, substantially as described.

2. A press as claimed in claim 1, wherein the piston is substantially in the form of a hemisphere, the base'of which has an area which is slightly smaller than the cross sectional area of the cylinder, substantially as described.v

3. A press as claimed in claim 1, wherein the cylinder is surrounded by a heating jacket. r

4'. A press as claimed in claim 1, wherein the piston is provided with a plurality of narrow slots which during the pressing operation are in communication at one side with the said space of decreasing cross-sec tional area, and at the other side with the atmosphere.

5. A press as claimed in claim 4:, wherein the piston and the cylinder are composed of a plurality of disks and distance pieces for spacing the disks with respect to each other. 7 V 6. A press as claimed in claim 4, wherein the piston is composed of a plurality of concave-convex disks and distance pieces for spacing the disks.

T. A press as claimed in claim 4 wherein.

the piston is mounted in such manner that it may be rotated about the axis during or at the end of a pressingoperation.

8. A press as claimed in claim 3, wherein the cylinder wall is provided with a plurality of narrow slots opening both in the cylinder and in the heating jacket.

9. A press as claimed in claim 8, wherein 11. A press of the character described ineluding a cylinder, a piston in the cylinder consisting of a body having a hollow head formed with a plurality of narrow annular slots in communication with the cylinder, and each slot having a cross sectional area which decreases in the direction from the interior of the hollow head to the outer surface thereof, substantially as described.

12. A press of the character described inclucling a perforate cylinder having the respective ends open, a cylinder cover arranged at one end of the cylinder, a piston arranged at the other end of the cylinder, the cover and the piston being provided with hemispherical shaped heads and mounted so that they may be moved relative to each other.

13. A press of the character described in cluding a perforate cylinder having open ends, a cylinder cover arranged at one end of the cylinder, a piston arranged at the other end of the cylinder, a jacket surround ing the cylinder in spaced relation and supporting the cylinder and having openings in its ends for accommodating the cylinder cover and the piston.

14. A press of the character described including a perforate cylinder, a jacket surrounding the cylinder in spaced relation thereto, a cylinder cover for the cylinder and a perforate hollow headed piston operating in the cylinder for coacting with the cylinder and the cylinder cover.

In testimony whereof I afiix my signature.

ABRAHALI TEN BOSCH. 

